A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-energy exhaust gas flow. The high-energy exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes low and high pressure compressors, and the turbine section includes low and high pressure turbines.
Shafts coupled between the turbine and compressor sections are supported on bearings disposed within bearing compartments. The bearing compartments are isolated from high pressure and temperature regions within the engine. To maintain the environment within a bearing compartment a seal between a static and rotating part is required. Seals are typically biased against a rotating face at a defined pressure to provide the desired seal. Such seals can wear prematurely if pressures increase during wear and operation.
Turbine engine manufacturers continue to seek improvements to engine performance including improvements to part life, engine assembly, maintenance and thermal, transfer and propulsive efficiencies.